Wallum Freshwater Biogeographic Province

Wallum Freshwater Biogeographic Province – Hydrology

• Perennial streams
• Chain-of-pond streams

Perennial streams

Chain-of-pond streams

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Little hydrology data has been collected and flow monitoring is minimal.

Water systems, both standing and running, are fed from the same water source—regional and perched aquifers[7].

Unconfined bodies of groundwater are present beneath North Stradbroke, Moreton and Bribie islands, and Cooloola-Teewah sand mass on the mainland[7][3]. These regional aquifers are typically located between the Quaternary sand deposits and older bedrock of Wallum islands, characterised by a gentle dome-shape[4].

They are the result of high run-off infiltration into permeable substrates, and the density difference in fresh and sea water creating suppressive forces on the watertable[5][6][7][2].

Perched groundwater is common in the FBP, and the result of impermeable substrate layers (see Geology) inhibiting the downward movement of water, consequently forming an aquifer above the regional groundwater body[4][7][2].

Recharge of regional and perched aquifers is solely reliant on rainfall infiltration, with 30% of rainfall passing to the primary watertable on North Stradbroke Island[5][7][2].

The ground and surface water systems of Wallum FBP are strongly linked in a complex relationship, and often in direct contact[1]. A long-term balance exists between recharge and discharge, with a stable distribution of groundwater as outflow at the coastline, to streams, and in shallow areas of groundwater as evapotranspiration[3]. The constant connection to groundwater in Wallum FBP has led to largely perennial riverine systems.

Perennial streams

The perennially available water source buffers the variations in rainfall across seasons, as demonstrated by the Blue Lake Overflow Creek (North Stradbroke Island) hydrograph. Slower water movement and some return seepage to the sand are typical and the result of a sand and vegetation matrix within the streams. Often, over the course of the entire stream length, sections will be gaining water, while others will be losing water.

Chain-of-pond streams

Chain-of pond streams represent forms of palustrine wetland, with little overall discharge or velocity.

Where connection exists between ponds, flow may occur both above and below ground. These systems are unlikely to be connected to regional or perched aquifers, and are largely rainfall fed.

References

1. ^ Armstrong, TJ & Cox, ME (2002), The relationship between groundwater and surface water character and wetland habitats, Bribie Island, Queensland. [online], Groundwater Investigations Repository, QUT Institute of Sustainable Resources. Available at: https://www.researchgate.net/publication/228455469_The_relationship_between_groundwater_and_surface_water_character_and_wetland_habitats_Bribie_Island_Queensland.
2. ^ a b c Cox, M & Labadz, M (2008), 'Quaternary sandy aquifers bounding Moreton Bay, SE Queensland, Australia: complex coastal hydrological systems', Proceedings of the 36th IAH Congress. Integrating Groundwater Science and Human Well-being, Toyama, Japan. [online], QUT. Available at: https://coastalresearch.csiro.au/?q=node/287.
3. ^ a b Department of Natural Resources and Mines (2006), Draft progress report, south east Queensland, potential groundwater resources: sandmass aquifers, Queensland Government.
4. ^ a b James, PM (1984), 'Perched lakes and water table windows : A note', Focus on Stradbroke: New information on North Stradbroke Island and surrounding areas 1974-1985; Royal Society of Queensland Symposium, North Stadbroke Island, 11-12 August 1984, Boolarong Publications and Stradbroke Island Management Organisation, Brisbane, eds. R.J. Coleman, J. Covacevich & P. Davie.
5. ^ a b Laycock, JW (1975), 'Hydrogeology of North Stradbroke Island', Proceedings of the Royal Society of Queensland, vol. 86, no. 4, pp. 15-19, Royal Society of Queensland.
6. ^ Laycock, JW (1975), 'North Stradbroke Island hydrogeological report', GSQ Report, vol. 88, Geological Survey of Queensland.
7. ^ a b c d e Marshall, J, McGregor, G & Negus, P (2006), Assessment of North Stradbroke Island groundwater dependent ecosystems: Potential responses to increases in groundwater extraction, Department of Natural Resources and Water, Queensland Government.

Last updated: 22 March 2013